The timing of NASA Administrator Sean O’Keefe’s sudden announcement Monday that he was resigning from the space agency to return to the academic world suggests his reasons were more complicated than he stated in public.

Moreover, despite the overall excellent job he has done, O’Keefe’s exit from NASA possibly is the best thing that could have happened for human space flight, for the Hubble Space Telescope, and for the American space program itself.

In his letter of resignation released Monday, O’Keefe cited family concerns. The job of administrator required him to work too often on weekends and evenings, he wrote, and with one child heading to college and two others at home, he wanted more time to be with his family.

Other reports said O’Keefe had hoped for an appointment to a higher cabinet position in Bush’s second term, and when such an appointment did not materialize he decided it was time to return to the academic world.

Timing is everything, however, and one wonders if the resignation — announced only five days after a National Academy of Sciences committee on the status of the Hubble Space Telescope bluntly rejected O’Keefe’s position on servicing the Hubble — had more to do with the committee’s position than family considerations or political disappointment.

Last January, O’Keefe shocked both the public and the astronomy community when he canceled the last scheduled shuttle servicing mission to Hubble. The ensuing uproar forced O’Keefe not only to request a review of the telescope’s future by the academies, but also to consider using robots to keep Hubble operating.

Since last spring, the space agency — under O’Keefe’s enthusiastic leadership — has aggressively pursued the robotic option, improvising a cutting-edge project nearly from scratch.

Many in the aerospace community have harbored doubts about this strategy, however. They wonder whether robotic technology has been sufficiently developed and tested to be given such an important task.

Timing is involved in this issue, too. Hubble’s batteries and gyros have a limited lifespan and will fail sometime before 2009, so any robotic mission would be under incredible time pressure. Some experts have questioned whether it is possible to design, build and launch such experimental technology within such a short time and have it succeed.

The national academies panel report was remarkably blunt.

“The likelihood of successful development of the (Hubble) robot servicing mission within the baseline 39-month schedule is remote,” the report said.

Instead, the committee recommended that NASA dispatch the space shuttle and humans to service the orbiting observatory.

The public response was immediate. Florida Today, in a Dec. 10 editorial, said “NASA chief Sean O’Keefe should give the order to save Hubble.” The newspaper added, “If O’Keefe won’t give the repair a go-ahead, Congress should make him.”

Several members of Congress — Sen. Barbara A. Mikulski, D-Md., and Rep. Sherwood Boehlert, R-N.Y. — have announced they will be holding hearings on Hubble’s rescue when they convene in February. Boehlert is the Chairman of the House Committee on Science.

O’Keefe, repeatedly and publicly — including in an appearance before the national academies committee — said he opposes sending humans into space to fix the Hubble. The committee report painted him into a corner, however, and placed him under under enormous pressure to change his mind.

It is questionable whether anyone would criticize him if he did. The Hubble’s spectacular success over the past decade has made it an icon of civilization. There is no doubt both the American public and the international community want it saved. Chances are, O’Keefe would have been lauded for being courageous and open-minded if he reversed himself.

Whatever his decision, O’Keefe’s accomplishments since he took over NASA in 2001 have left him in good stead. The agency is in its strongest position in decades, with a growing budget, a strong commitment from Congress and President George W. Bush for a bold new space exploration vision, and a revitalized bureaucracy focused intensely and passionately on achieving that new vision.

Thus, O’Keefe the administrator was ideally positioned to authorize a shuttle mission to Hubble. The problem was whether O’Keefe the man had the stomach for sending humans back into space.

He has described himself as an academic and a “bean-counter,” who was not part of the risk-taking space exploration community. More to the point, in his testimony to the national academies committee earlier this year he expressed a strong emotional reluctance about flying humans in space, resulting from his terrible post-Columbia accident experience.

“If we fail … on a (human) servicing mission,” he told committee members, “then we’ll have another set of memorials that I have no intention of presiding over. I’ve done that once and it was emblazoned in my memory like it was yesterday. There’s not a day that goes by I don’t think of that.”

O’Keefe’s desire to avoid what he admits is a risky endeavor raises doubts whether he would have been able to send astronauts beyond Earth orbit and to the moon, as required by President Bush’s new space initiative. Such missions are much more risky than a journey to Hubble.

Exploring the solar system will be a noble and exciting enterprise, but it also will be difficult — even brutal. It will require its participants to be cold-hearted and determined, even in the face of terrible adversity.

The families of the seven astronauts who died on Columbia demonstrated that determination when they announced, shortly after the deaths of their loved ones in February 2003, that the space program should move forward.

“Although we grieve deeply, as do the families of Apollo 1 and Challenger before us, the bold exploration of space must go on,” they said in a statement.

O’Keefe has not had to face sending anyone into space since the Columbia accident. Now, however, with the shuttle’s return to flight looming next May, and with the Hubble decision remaining, he would have had to revisit that reality.

It appears from his resignation he would rather not, deciding instead to leave the risks of space exploration to others. In the end, O’Keefe’s decision might be best for all.

Meanwhile, those whose names are currently floating in the media as candidates to head NASA all have credentials closely linked and supportive of manned space exploration. Perhaps more important, some of those candidates have risked their own lives in the air and beyond.

Four possibilities — Charles Bolden, Ron Sega, Robert Crippen and Frank Culbertson — are former astronauts, while a fifth — Ronald Kadish — was an Air Force pilot with 2500 flight hours to his credit. Any one of these men would be less squeamish than O’Keefe about sending humans into space.

The national academies report and O’Keefe’s departure makes it much more likely now that the shuttle once again will become the method of choice to rescue Hubble, and once NASA commits to sending astronauts to Hubble, it will be in a far better position to send humans to the moon and beyond.

So, the events of the past week may have improved the future of the American space program — far more than one would have thought at first glance.